Centrifugal blower rotor



Sept. 13, 1938..

' G. W..MCKEEl CENTRIFUGAL BLOWER ROTOR Filed Oct. 20, 1957 Patented Sept. 13, 1938 UNITED STATES wir@ CENTRIFUGAL BLOWER ROTOR Garnet W. McKee, Rockford, Ill.

Application October 20, 1937, Serial No. 169,971

5 Claims.

The present invention relates generally to blade equipped rotors. More particularly the invention relates to that type of rotor which together With a conventional surrounding casing having an inlet opening in the side thereof and a peripheral outlet forms a centrifugal blower, consists of a cylindrical hub with a shaft opening therethrough and an annular series or set of equidistantly spaced radial plate metal blades around the hub, and is adapted for high speed drive and to draw gas or air at either normal or high temperature through the inlet opening in the side of the casing and to discharge the gas or air under pressure from the casing via the peripheral outlet thereof. Y

One object of the invention is to provide a rotor of this type which is an improvement upon and embodies certain inherent advantages over previously designed rotors of the same general design and for the same purpose and is characterized by the fact that the blades thereof are so arranged and anchored that they are free during drive of the rotor to swing or move into truly radial relation with the hub in response to the action of centrifugal force and hence regardless of the speed of rotation or the temperature to which they are subjected they maintain the rotor as a whole in balanced relation and effectively prevent the setting up of strains or stresses which would cause vibration and resultant crystallization of parts.

Another object of the invention is to provide a blade-equipped rotor of the type under consideration in which the baldes are formed or arranged in pairs and each pair of blades is in the form of a one piece stamping and embodies a hub-engaging cross piece which extends between the inner or root portions of the blades and is joined to such portions by uniformly rounded or curved bends.

A further object of the invention is to provide a centrifugal blower rotor of the type and character last mentioned in which the cross pieces between the inner or root portions of the pairs of blades are curved conformably to the outer periphery of the hub and the latter embodies outwardly extending annular members at its ends and also longitudinally extending pins which extend between and are connected to the members and t within the bends between the cross pieces and the root portions of the blades in such manner that they serve to hold the blades in connected relation with the hub.

A still further object of the invention is to provide a blade-equipped rotor of the type under consideration which is especially adapted or designed for use in connection with a small high speed blower and may be produced at a lower cost than that which forms the subject matter of an application for United States Letters patent filed by me of even date herewith Serial No. 169,970.

Other objects of the invention and the various advantages and characteristics of the present blade equipped rotor will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

VIn the drawing which accompanies and forms a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a transverse sectional View of a centrifugal blow-er rotor embodying the invention, illustrating in detail the arrangement and design Aof the equidistantly spaced radial plate metal blades and the manner in which the blades are held in anchored or connected relation with the hub;

Figure 2 is a longitudinal sectional view taken on the line 2 2 of Figure 1 and showing the design and construction of the hub of the rotor and also the manner in which the pins are caru ried by the outwardly extending annular members at the ends of the hub; and

Figure 3 is a perspective of one of the unit type pairs of blades around the hub of the rotor.

The rotor which is shown in the drawing consttutes the preferred embodiment of the invention. It is designed in connection with a conventional or standard casing (not shown) having an inlet opening in the side thereof and a peripheral outlet to form a centrifugal blower and is adapted to be driven at a comparatively high speed and to draw gas or air at either normal or high temperature inwardly through the inlet opening in the side of the casing and to discharge the gas or air under pressure via the Til) hub. 'Ihe hub is adapted to be keyed or otherwise xedly secured to the drive shaft and embodies a pair of outwardly extending annular members I and an annular series of longitudinally extending pins 8. The members 'I are in the form of integral annular flanges at the ends of the hub and are each provided with an annular series or set of circular holes 9. As shown in Figure 2 the holes 9 in one outwardly extending annular member I correspond in number to and are yaligned with the holes in the other member. The pins 8 are formed of steel or any other suitable material and are slightly longer than the hub 4. They are externally positioned with respect .to thehub and serve as hereinafter described, to hold the blades 5 in connected or anchored relation With the hub. The ends of the pins extend through the holes 9 in the members 'I and have enlarged polygonal heads I in engagement with the inner face of one member and cotter pins I I in opposed relation with the outer face of the other member and serving with the heads to hold the pins against axial displacement with respect to the hub.

The blades are formed of plate metal or llike comparatively stiff material and are of uniform thickness throughout. They are spaced equidistantly apart and extend radially from the outer periphery of the hub 4. The outer and central portions 'of the blades are flat and operate during drive of the rotor to impel and Aplace under pressure the .gas or air which is sucked or drawn inwardly through the inlet opening in the side of the casing with which the rotor is associated. As shown in Figures 1 and 3 the blades are formed or arranged in pairs and each pair of blades is in the form of a one-piece stamping and embodies a hub engaging cross piece I2 which extends between the inner or root portions ofthe blades and is joined to such portions by uniformly rounded or curved integral bends I3. The cross pieces I2 are curved or bent conformably to the outer periphery of the hub 4. The bends I3 and the cross pieces are of the same width as the blades and fit directly against said outer periphery of the hub. The pins 8 correspond in number to the blades 5 and are arranged so that there are two of them for each pair of integrally formed unit type blades. They t within the yuniformly roundedor curved Abends I3 between the cross pieces I2 and the inner or root portions of the blades and are spaced from the outer periphery of the hub a distance equal to the thickness of the bends with the result that they serve to hold the latter together with the cross pieces in' abutting and angular relation with the hub. By reason of the fact that the bends extend around the outer side portions of the pins the blades or cross pieces are held against circumferential movement with respect to the hub. The outer faces of the bends are curve-d conformably to the periphery of the pins and hence there is no looseness between the bends and the pins. The side edges of the inner or root portions of the blades abut against the inner faces of the outwardly extending annular members "I at the ends of vthe vhub with the result that the blades are held against longitudinal movement relatively to the hub. Screws I4 extend through the central portions of the cross pieces I2 into internally threaded radially extending sockets I5 in the hub and serve additionally to hold the blades and-cross pieces in place. The blades in View of the specic manner in which they are connected or anchored to the hub by the pins 8 and the bends I3 are free to swing or move into truly radial relation with the hub in response to the action of centrifugal force during high speed drive of the rotor and hence regardless of the rotational speed thereof or the temperature to which they are submitted they do not unbalance the rotor as a whole or set up any strains or stresses which would result in vibration and cause crystallization of parts. During starting of the rotor the blades due to their inertia tend to tilt rearwardly. Such action does not, however, impose any strain or stress upon the cross pieces I 2 between the inner or root ends of the blades for the reason that the tendency of the leading blades of the pairs to urge inwards the front or leading portions of the cross pieces is counteracted by the tendency of the trailing blades of the pairs to move the trailing portions of the cross pieces away from the hub.

The rotor is assembled by first arranging the blades5 Yin radial relation with the hub so that the integral connecting cross pieces I2 abut against the outer periphery of the hub and the bends I3 are disposed in registering relation with the holes 'I in the outwardly extending annular members 9 at the ends of the hub. Thereafter the screws I4 are inserted through the central portions of the cross-pieces I2 and into threaded engagement with the internally threaded sockets i5. At ythe conclusion of this step or operation the pins 8 are brought into their proper position by driving them through the holes 9 and into seated relation with the outer curved faces of the bends I3.

The herein described centrifugal blower rotor due to the `design and arrangement of the blades maintains automatically its proper balance regardless of rotational speed or the temperature to which it is subjected. It has special utility in connection with a high speed blower for hot gas or air and may be manufactured at a low and reasonable cost since it consists of but a small number of parts. Due to the general design and arrangement of parts the rotor may be balanced tc a nicety and contemplates true radial relationship of the blades with respect to the hub at all times.

The invention is not to be restricted to the specific details set forth, since these may be modied within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by `Letters Patent is:

l.. A centrifugal blower `rotor comprising a hub adapted to be connected to and driven by a shaft and having outwardly extending members at its ends, pairs of radially extending blades yarranged in an annular series around the hub and i each embodying a hub engaging cross piece between and connected by bends to the inner or root portions of the blades thereof, and pins extending between and carried by said members and arranged so that they t in the 'bends respectively and serve to hold the cross pieces in place against the hub.

2. A centrifugal blower rotor comprising a hub adapted to be connected to and driven by a shaft and having outwardly extending members at its ends, pairs of radially extending blades arranged in an annular series around the hub and each embodying a hub engaging cross piece between and connected by uniformly rounded hub engaging bends to the inner or root portions of the blades thereof, and cylindrical pins extending parallel to and spaced slightly outwardly of the hub and having their ends extending through holes in said members and their central portions thereof fitting in the bends respectively and serving to hold the cross pieces in place against the hub.

3. A centrifugal blower rotor comprising a cylindrical hub adapted to be connected to and driven by a shaft and having outwardly extending annular members at the ends thereof, equidistantly spaced pairs of radially extending blades arranged in an annular series around the hub and each embodying a cross piece curved conformably to and tting against the outer periphery of the hub and extending between and connected by integral uniformly rounded bends to the inner or root portions of the blades thereof, and means for holding the cross-pieces in place against the hub consisting of screws extending through the central portions of the cross-pieces and into the hub and removable cylindrical pins extending parallel to and spaced slightly outwardly of the hub and having their ends extending through holes in said members and the central portions thereof fitting in the bends respectively.

4. A centrifugal blower rotor comprising a hub adapted to be connected to and driven by a shaft and having outwardly extending members at its ends, substantially equidistantly spaced blades' extending radially outwards from the hub and having cross pieces at the inner ends thereof together with uniformly rounded bends between them and said cross pieces, and means for securing said cross pieces in attached relation with the hub comprising individually removable cylindrical pins extending parallel to and spaced slightly outwardly of the hub and having the ends thereof extending through aligned holes in said members the central portions thereof fitting in the bends respectively.

5. A centrifugal blower rotor comprising a cylindrical hub adapted to be connected to and driven by a shaft and having outwardly extending annular members at its ends, substantially equidistantly spaced blades extending radially outwards from the hub and having cross pieces at the inner ends thereof tting against and curved conformably to the outer periphery of the hub and joined to said inner ends of the blades by uniformly rounded or curved bends, and means for securing said cross pieces in place against the hub comprising removable cylindrical pins extending Vparallel to and spaced slightly outwardly of the hub and having the ends thereof extending through aligned holes in said members and the central portions thereof fitting in the bends respectively.

GARNET W. MCKEE. 

